Apparatus for applying an aqueous bituminous emulsion to a fibrous web



w s 1 M a 1. RM Y w T w c M 2 W NM R 2 E O 6 VR. T 2 s m T T 2 A m m m 2 M C. R. M DoNALD APPARATUS FOR'APPLYING AN AQUEOUS BITUMINOUS EMULSION TO A FIBROUS WEB Dec. 23, 1952 Filed Dec. 4, 1948 C. R. M DONALD APPARATUS FOR APPLYING AN AQUEOUS BITUMINOUS Dec. 23, 1952 EMULSION TO A FIBROUS WEB Filed Dec. 4, 1948 2 SHEETS-SHEEET 2 7'1rillI/Illllllfl/lllllfllll W ATTO R N EY Patented Dec. 23, 1952 APPARATUS FOR. APPLYING- AN AQUEOUS BITUMINOUS EMULSION TO A FIBROUS. WEB

Chester Rice MacDonald, Ramsey, N. .l., assignor to The Patent and Licensing Corporation, New York, N.1Y'., av corporation of Massachusetts Application, December 4, 1948,, Serial No. 63,486

1 Claim. 1.

This invention relates to improvements in apparatus for making waterproofed multi-ply paper and is particularly concerned with improvements in a device for applying a film of an aqueous web.

machine.

roll.

to the fibrous web.

effected without the use of eXteriorly positioned circulating means.

A still further object of the invention is to provide an improved emulsion applicatorroll.

In accordance with the invention I provide an emulsion applicator roll which is hollow throughout substantially its entire length, and has. at least at one of its ends, a closure section provided with ducts or passageways extending obliquely through the closure section and cominciined ducts exert a pumping action upon the emulsion as the applicator roll revolves and propel the emulsion through the interior of the roll and thereby maintain the emulsion in constant and effective circulation in the trough in which ther advantages and features of the invention will be apparent from the detailed description Fig. 1 is a plan view of an emulsion applicator Fig. 2 is a view in section of the applicator roll Fig. 3 is an enlarged end view of the roll shown Fig. 4 is a view in section of a modified form of Fig. 5 is a sectional view of the applicator unit cator roll to the blanket of the paper making Fig. 6 is a developed view taken along theline A through the roll shown in Fig. 5, and out along Referring to the drawings, the numeral Id desl3, end walls 55 and it a bottom I-F. A

A cylindrical ap licator roll 25, provided at each nd'with stub shafts L and 28, is longitudinally mounted in trough 28 between partition walls 22 and 23. The shaft 2'? passes through aligned recesses in end wall .5 and partition wall 22', respectively, and is supported in a bearing 29 secured as by Shaft 28 passes through recesses in partition wall 23 and end wall IS,

A liquid-tight gland 3| bituminous emulsion to a freshly formed fibrous 5 Waterproofed mul'ti-ply paper or paper board, such as boxboar'd, ismanufactured by forming a plurality of fibrous plies on a cylinder type mu-nicating with the interior of the roll. These paper-making machine and applying a film of emulsified bitumen between selected'plies of the sheet simultaneously with the formation thereof. The waterproofing film is commonly applied by an emulsion applicator unit interposed between two of the cylinder moulds of the paper making the roll is mounted.

This type of process is described, for example, in U. S. Patent 1,616,901, dated February 8, 1927. Emulsion applicator units which are hich follows and from the accompanying drawused for this purpose comprise, essentially, a ings in which: screen-covered roll which continuously revolves in a body of bituminous emulsion maintained in roll embodying the invention. a suitable trough. A film of the emulsified bitumen is picked up by the screen on the roll and shown in Fig. 1. is transferred to the lower surface of a wet r fibrous ply as it passes over the applicator roll. in Fig. 2. Fresh supplies of emulsion of the requisite consistency are continuously introduced into the the roll shown in Fig. 1. trough to replace the emulsion taken up by the showing the relationship of the emulsion appli- In. applicator units commonly employed, there so is a tendency for localized changes in the conmachine and centration of bitumen in the emulsion to occur, owing to lack of adequate means for maintaining the homogeneity of the emulsion throughout the lineB. the trough, and unequal distribution of the bitumen in the trough results. This, of course. leads ignates generally the rectangular'vat of the-emultounequal distribution of bitumen on the screen sion appli ator unit, formed by side walls f2 and of the roll and subsequently in the film applied trough 25!, adaptedtocontain the emulsified bitu- Attempts to overcome this condition have in- 40 men, is formed within vat Hi by spaced transverse volved somewhat elaborate systems of circulapartition walls 22 and 23. secured as by Welding to tion wherein the emulsion is pumped out of one side walls l2 and 53 and bottom 5-1. end of the trough and reintroduced at the other end. This approach tothe problem is somewhat cumbersome, is not altogether satisfactory and may adversely afiect the emulsion.

It is the principal object of this invention to provide means for maintaining circulation of bi- I tuminous emulsion in an emulsion applicator unit bolting to end wall :5. which does not have the aforesaid disadvantages.

It is a further object of the invention to prorespectively, and is supported in a bearing 30 vide an emulsion applicator unit for use in the secured. to end wall It. manufacture of waterproofed multi-ply paper is provided on shaft 2'! adjacent partition wall wherein circulation of emulsion in the unit is 22 to prevent escape of emulsion from trough 20 and a similar gland 32 is mounte on shaft 28,

adjacentpartition wall 23. Emulsion of prede termined consistency is continuously supplied to trough 29 through an inlet pipe 94 which passes through aligned openings in end wall 15 and.

partition wall 22. A sprocket wheel 99 is mounted on shaft 28 exteriorly of vat l9. Sprocket wheel 39 may be connected as by chain 48, to any suitable source of power.

Referring particularly to Fig. 2 and Fig. 5, the applicator roll 25 is hollow except for closure sections in the form of plugs 45 and '46 which are positioned in either end of the roll and in which are secured the stub shafts 21 and 29. The plugs 45 and 45 are provided with inclined ducts 49 and 49 respectively, which progress obliquely through the plugs and provide access to the interior of roll 25. In the embodiments illustrated, ducts 48 and 49 are kidney-shaped in cross-section and extend at an angle of about 45 from one end of the plug to the other. While I have found three ducts in each of the plugs 45 and 49 particularly effective, more or fewer ducts may be provided. Also, the angle of inclination of the ducts 48 and 49 may vary over a wide range. Preferably, however, the ducts 49 and 49 should be inclined at an angle between 30 and 60.

As will be seen, particularly from Fig. 2, the ducts 48 in plug 45 are inclined in a direction pposite to that of the ducts 49 in plug 45, when viewed from the shaft ends. It will be observed, however, that the ducts are complementary, i. e. the ducts 48 when viewed from outside the roll are inclined in the same direction as ducts 49 when viewed from inside the roll. Thus, both sets of ducts propel the emulsion in the same direction.

As the roll 25 revolves in trough 29, ducts 48 and 49 exert a pumping action on the emulsion, drawing it into the interior of roll 25 at one end thereof and expelling the emulsion into the trough 20 at the other, thereby maintaining a circulation of the emulsion in the' trough 20. Thus, for example, ducts 49 in plug 46 will draw emulsion into the interior of roll 25, at one end of trough 28, assuming the roll 25 rotates in a clockwise direction, as viewed from the left of Fig. 2, and ducts 48 in plug 45 will expel emulsion from the interior of roll 25 at the opposite end of the trough. On the other hand, assuming the roll 25 rotates in a counter-clockwise direction, emulsion will be drawn in through ducts 48 and expelled through ducts 49. Thus, during the operation of the emulsion applicator unit, the ducts 48 and 49 serve to circulate continuously the emulsion in trough 20 and thereby maintain the emulsion in a substantially homogeneous condition throughout trough 28, regardless of the direction of rotation of the roll 25.

An arouate baffle 50, supported below roll 25 by legs 5| extends longitudinally of the emulsion trough 20 between partition walls 22 and 23. As the roll 25 revolves, bafiie 59 effects increased agitation and mixing of the emulsion, thereby assisting in maintaining the homogeneity of the emulsion.

The outer surface of the roll 25 is formed with a series of parallel longitudinal ridges 52 over which a screen 54 is wound, the screen 54 being in contact with the roll 25 only along the apices of the ridges 52. The invention is, however, not limited to an applicator roll having a particular surface configuration. The ridges 52 provide a particularly effective method of supporting the screen 54 and at the same time permit free access of air to the underside of screen 54 and thus prevent the development of suction between the applicator roll and the wet web which passes over it during the operation of the machine.

Referring to Fig. 5, the roll 25 is shown in operative position in contact with a fibrous web 58 adhering to the underside of a blanket 69. A film of the emulsion 62, contained in trough 28, is picked up by screen 54 and transferred to web 58 upon rotation of the roll 25. A tension roll 64 maintains the web 58 in contact with roll 25.

While I have described a preferred embodiment of my invention, it will be apparent that my apparatus may take somewhat modified forms. Referring to Fig. 4, for example, the stub shafts 21 and 28 may be replaced by a continuous shaft 65 and, although somewhat less eflicient circulation is attained, one of the perforated closures may be substituted by a spider 96 or other conventional support for the shaft 65.

Obviously, other modifications may be made without departing from the scope of the invention as defined in the appended claim andit is intended, therefore, that all matter contained in the foregoing description and in the drawings shall be interpreted as illustrative and not in a limiting sense.

I claim:

An applicator roll comprising an elongated hollow cylinder, closure plugs at each end of said cylinder having a plurality of ducts therethrough extending lengthwise obliquely to the axis of said cylinder in the manner of a screw thread, axial stub shafts fixed to said closure plugs and adapted for the rotation of said cylinder, a multiplicity of parallel longitudinal ridges on the outer surface of said cylinder and a screen wrapped around said cylinder outside said ridges.

' CHESTER RICE MACDONALD.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 436,525 Hemphill Sept. 16, 1890 709,190 Wright Sept. 16, 1902 825,094 Weinland July 3, 1906 913,731 Kay Mar. 2, 1909 944,607 Goldsmith Dec. 28 ,1909 1,406,275 Norman Feb. 14, 1922 1,497,196 Potdevin .1 June 10, 1924 1,724,137 Kirschbraun et al. Aug. 13, 1929 1,955,442 Schwartz Apr. 17, 1934 2,157,874 Webb May 9, 1939 2,249,182 Sidebotham et al. July 15, 1941 2,306,583 Yost Dec. 29, 1942 2,352,978 Shoemaker July 4, 1944 

